1. Field of the Invention
The present invention relates to an improved scoring apparatus of the type used in box making operations for the purpose of creating strategically located scores and cuts in box blanks that define the folding lines and tabs of the finished boxes. More particularly, the invention relates to an improved scoring apparatus having a selectively retractable scoring blade that can be pivoted between an extended position and a retracted position during operation of the scoring apparatus for permitting scoring and cutting along any position of the box blanks.
2. Description of the Prior Art
Conventional box making operations generally involve the steps of cutting a box blank from a sheet of corrugated paperboard, scoring, cutting and/or slotting the box blank at strategic locations to form the fold lines, flaps, and tabs of the finished box, and folding the box blank along the fold lines to form a finished box.
The scoring, cutting and slotting operations are typically performed in scoring and cutting apparatuses having adjacent, serially aligned scoring and cutting cylinders or wheels rotatably mounted on powered drive shafts. Scoring blades and cutting blades are fixed to the rotating scoring and cutting cylinders for making scores and cuts in the box blanks as the box blanks are fed through the rotating scoring and cutting cylinders. Since the scoring blades and cutting blades rotate with the cutting cylinders, they score, cut and/or slot the blanks during each revolution of the cutting cylinders to create a series of spaced score lines and cuts used to form the fold lines, panels and flaps of a finished box.
The scoring and cutting apparatuses of the type described above suffer from several limitations that limit their utility. For example, the cutting blades and scoring blades on prior art scoring and cutting apparatuses are typically fixed to their respective rotating cylinders. Thus, a slot or score line is made in the box blanks each and every time the rotating cylinder completes a revolution. This limits the size of boxes that can be formed using the scoring and cutting apparatus because the maximum box blank length which can be handled is determined by the diameter of the rotating cutting cylinder. If it is desired to produce boxes that require greater spaces between the score lines and/or cuts, a larger, more expensive rotating cylinder must be provided.
Slotter wheel devices with adjustable slotter blades are known in the art. For example, U.S. Pat. No. 4,805,502 describes a slotter wheel device including a wheel-supporting shaft having an eccentric axis permitting selective movement of the supported slotting blades to a non-cutting position. However, to shift the slotting blades to the non-cutting position, it is necessary to stop the operation of the wheel, manipulate the eccentric axis to alter the blade position, and then resume slotting operations. Thus, the '502 device is incapable of positioning a slotting blade between a cutting position and an idle, blank-clearing position during rotation of the slotting wheel and cannot accommodate oversized box blanks.
U.S. Pat. Nos. 5,297,462 and 5,327,804, hereby incorporated by reference, disclose slotter wheel mechanisms having dynamically retractable slotter blades that allow the formation of boxes of various sizes. These patents provide greatly improved box making operations which allow the "skipping" of cutting during one or more successive slotter wheel revolutions. With this configuration, blanks of virtually any size may be readily slotted without stopping the slotter wheel device and without the need for employing larger diameter slotter wheels.
Although the '462 and '804 patents provide selectively retractable slotter blades, their scoring blades remain fixed. Therefore, although these devices can make slots anywhere along the length of the box blanks, they can place score lines for folding the boxes only at fixed locations.
Accordingly, there is a need for an improved rotary scoring apparatus that permits selective positioning of the scoring blades during rotation of the scoring cylinder so that blanks of virtually any length can be formed with standard sized scoring machines. There is also a need for an improved scoring apparatus that performs the above-described features yet is relatively simple and inexpensive to construct.